問題描述

我正在使用 Mockito 進行后期單元測試.我對何時使用 doAnswer 和 thenReturn 感到困惑.

I am using Mockito for service later unit testing. I am confused when to use doAnswer vs thenReturn.

誰能幫我詳細介紹一下?到目前為止，我已經用 thenReturn 進行了嘗試.

Can anyone help me in detail? So far, I have tried it with thenReturn.

推薦答案

當你在 mock 一個方法時知道返回值時，你應該使用 thenReturn 或 doReturn稱呼.調用模擬方法時會返回此定義的值.

You should use thenReturn or doReturn when you know the return value at the time you mock a method call. This defined value is returned when you invoke the mocked method.

thenReturn(T value) 設置調用方法時要返回的返回值.

thenReturn(T value) Sets a return value to be returned when the method is called.

@Test
public void test_return() throws Exception {
    Dummy dummy = mock(Dummy.class);
    int returnValue = 5;

    // choose your preferred way
    when(dummy.stringLength("dummy")).thenReturn(returnValue);
    doReturn(returnValue).when(dummy).stringLength("dummy");
}

Answer 用于在調用模擬方法時需要執行其他操作，例如當需要根據該方法調用的參數計算返回值時.

Answer is used when you need to do additional actions when a mocked method is invoked, e.g. when you need to compute the return value based on the parameters of this method call.

當您想使用通用 Answer 存根 void 方法時，請使用 doAnswer().

Use doAnswer() when you want to stub a void method with generic Answer.

Answer 指定了一個執行的動作和一個在你與 mock 交互時返回的返回值.

Answer specifies an action that is executed and a return value that is returned when you interact with the mock.

@Test
public void test_answer() throws Exception {
    Dummy dummy = mock(Dummy.class);
    Answer<Integer> answer = new Answer<Integer>() {
        public Integer answer(InvocationOnMock invocation) throws Throwable {
            String string = invocation.getArgumentAt(0, String.class);
            return string.length() * 2;
        }
    };

    // choose your preferred way
    when(dummy.stringLength("dummy")).thenAnswer(answer);
    doAnswer(answer).when(dummy).stringLength("dummy");
}

這篇關于Mockito:doAnswer Vs thenReturn的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！